80分超时无启发式代码：

#include <bits/stdc++.h>
using namespace std;
const int N=2e5+10;
vector<int> G[N];
int n, tsp, dfn[N], _dfn[N], siz[N], col[N], cnt[N], ans[N], tot;

void dfs1(int x, int xfa) {
    dfn[x] = ++tsp; _dfn[tsp] = x;
    siz[x] = 1;
    for(int y : G[x]) if(y != xfa) {
        dfs1(y, x);
        siz[x] += siz[y];
    }
}

void add(int x) { cnt[col[x]]++; if(cnt[col[x]] == 1) tot++; }
void del(int x) { cnt[col[x]]--; if(cnt[col[x]] == 0) tot--; }

void dfs2(int x, int xfa) {
    for(int y : G[x]) if(y != xfa) dfs2(y, x);
    
    for(int i = 0; i < siz[x]; i++) add(_dfn[dfn[x] + i]);
    ans[x] = tot;
    
    for(int i = 0; i < siz[x]; i++) del(_dfn[dfn[x] + i]);
}

int main() {
    scanf("%d", &n);
    for(int i = 1; i <= n; i++) scanf("%d", &col[i]);
    for(int i = 1, x, y; i < n; i++) {
        scanf("%d%d", &x, &y);
        G[x].push_back(y);
        G[y].push_back(x);
    }
    tsp = 0; dfs1(1, 0);
    memset(cnt, 0, sizeof(cnt));
    tot = 0; dfs2(1, 0);
    for(int i = 1; i <= n; i++) printf("%d ", ans[i]);
    return 0;
}

标程：

#include<bits/stdc++.h>
using namespace std;
const int N=2e5+5;
vector<int> G[N];
int n,tsp,dfn[N],_dfn[N],siz[N],son[N],col[N],cnt[N],ans[N],tot;
void dfs1(int x, int xfa)
{
	dfn[x]=++tsp; _dfn[tsp]=x;
	siz[x]=1;son[x]=-1;
	for(int y:G[x])if(y!=xfa)
	{
		dfs1(y,x);
		siz[x]+=siz[y];
		if(son[x]==-1 || siz[son[x]]<siz[y])son[x]=y;
	}
}
void add(int x){cnt[col[x]]++;if(cnt[col[x]]==1)tot++;}
void del(int x){cnt[col[x]]--;if(cnt[col[x]]==0)tot--;}
void dfs2(int x, int xfa)
{
	for(int y:G[x])if(y!=xfa && y!=son[x])dfs2(y,x);
	if(son[x]>0)dfs2(son[x],x);
	
	for(int i=0;i<siz[x];i++)
    {
        if(_dfn[dfn[x]+i]==son[x]){i=i+siz[son[x]]-1;continue;}
        add(_dfn[dfn[x]+i]);
    }
	ans[x]=tot;

	if(son[xfa]!=x) 
	{
		for(int i=0;i<siz[x];i++)del(_dfn[dfn[x]+i]);
	}
}
int main() 
{
    scanf("%d",&n);for(int i=1;i<=n;i++) scanf("%d",&col[i]);
    for(int i=1,x,y;i<n;i++) 
    {
        scanf("%d%d",&x,&y);
        G[x].push_back(y);
        G[y].push_back(x);
    }
    tsp=0; dfs1(1,0);
    memset(cnt,0,sizeof(cnt));
    tot=0;dfs2(1,0);
    for(int i=1; i<=n; i++) printf("%d ",ans[i]);
    return 0;
}